The present invention relates to horn control systems for model trains.
Model train systems have been in existence for many years. In a typical system, the model train engine is an electrical engine which receives power from a voltage which is applied to the tracks and is picked up by the train motor. A transformer is used to apply the power to the tracks. The transformer controls both the amplitude and polarity of the voltage, thereby controlling the speed and direction of the train. In HO systems, the voltage is a DC voltage. In Lionel systems, the voltage is an AC voltage transformed from the 60 HZ line voltage available in a standard wall socket.
In addition to controlling the direction and speed of a train, model train enthusiasts have a desire to control other features of the train, such as the whistle and other noises typically generated by a locomotive. Hobbyists strive to achieve realism in all facets of the model railroad layout, including the size, features, and sounds of the train. Lionel presently allows for control of the whistle by providing a horn button located on the transformer. When the button is activated, a DC voltage is imposed on top of the AC line voltage, which is then picked up by the locomotive. The horn has a single tone available. These previous horns produced sound in three simple repetitive segments, and limited the variety and qualities of sound available to the user to a single sound, variable in length by the amount of time the user held down the horn control button.
One method of achieving greater realism in the train sound is disclosed in Rexford, U.S. Pat. No. 3,389,822. This patent teaches a means for simulating the puffing sound of a locomotive by responding to the rotation of a wheel. In Smith, U.S. Pat. No. 2,882,834, a sound system is disclosed which produces pulsating engine sounds by varying the sound based on driving strength of the magnetic field of a solenoid in the train engine. One problem with such systems is that each produces only a limited range of sounds, based on a single set of inputs. Further, the user does not have complete control over the initiation and duration of the sound.
Another method, designed for trackless, remote control vehicles, is disclosed in Collier, U.S. Pat. No. 4,964,837 where a self-contained sound system is shown. The system produces specific sounds based on different sensor inputs, such as a crash, or the squeal of tires. Again, the system suffers in that the user does not have control over the initiation and duration of the simulated sounds. Each of the previous systems fall short in providing the desired realism required to accurately recreate the sound and feel of an actual vehicle such as a locomotive.
Accordingly, what is needed is a sound generation system which gives an operator the ability to simulate a wide variety of locomotive noises, or to create "signature" sounds like the engineers of a real train, thus increasing the amount of realism a hobbyist may achieve in a system.